1. Field
The present invention relates generally to the field of communications, and more particularly, to data communications in a communication system.
2. Background
In a wireless communication system, unnecessary and excessive transmissions by a user may cause interference for other users in addition to reducing the system capacity. The unnecessary and excessive transmission may be caused by inefficient flow of data in the communication system. The data communicated between two end users may pass through several layers of protocols for assuring proper flow of data through the system. Normally, a base station may receive a block of data for transmission to a mobile station. The block of data is encoded via a block outer code. The outer encoded data is partitioned into frames of data for transmission over one or more physical layer frames. Each physical layer frame of data is encoded using a physical code, and is transmitted over several time slots. The proper delivery of data in at least one aspect is assured through a system of checking for error in each frame of data, and requesting a retransmission of the same frame of data if an unacceptable error or error rate is detected in the frame of data. The block of data may be any type of data, for example, music data, video data, etc. As such, after receiving the frames of data of a bock of data, the mobile station reconstructs the block of data to play the music or video, for example.
More specifically, the wireless communication system may be operating in accordance with the code division multiple access (CDMA) technique which has been disclosed and described in various standards published by the Telecommunication Industry Association (TIA) and other standards organizations. Such standards include the TIA/EIA-IS-2000 standard. A copy of the standards may be obtained by accessing the world wide web at the domain: 3gpp2.org, or by writing to TIA, Standards and Technology Department, 2500 Wilson Boulevard, Arlington, Va. 22201, United States of America. In one aspect, the wireless communication system operating in accordance with the IS-2000 protocol has an option of providing supplemental channels to the mobile stations at fixed or variable data rates. The supplemental channels may be used to transmit a block of data to the mobile station at a fixed data rate or variable data rate. In another aspect, the wireless communication system operating in accordance with the IS-2000 protocol has an option of providing forward packet data channels (F-PDCH) to the mobile stations at variable data rates, variable physical layer frame durations, and variable modulation formats. The F-PDCHs may be used to transmit a block of data to the mobile station at a variable data rate. However, variable formats, including data rate, modulation and frame duration, communication may be possible in any wireless communication.
At fixed data rate and continuous transmission over the supplemental channel, the base station partitions the block of data in accordance with the fixed data rate. Each partition of the block of data may be multiplexed as a packet of data for transmission over a physical layer frame. A frame of data may be transmitted to the mobile station over several time slots. Since the data rate over the supplemental channel is fixed, each frame of data may have the same size data payload. As such, the packets of data from a partitioned block of data are also at the same size. Moreover, since the transmission is continuous, the mobile station can determined how much data is missing if it doesn't receive a frame. Therefore, the mobile station may easily determine the location of the retransmitted frame of data in the block and reconstruct the entire block of data.
However, reconstructing the block of data may not be feasible or easily possible when the data is transmitted to the mobile station at variable rate or in a discontinuous format. This is the case either when the transmission of the supplemental channel is discontinuous and unknown to the mobile station or the F-PDCH is used. For the F-PDCH, the size of the payload of a frame may vary from frame to frame. For variable data rate, the size of payload in each frame of data may vary. As such, the packets of data from the partitioned block of data are not necessarily at the same size. If a frame of data is received in error and, therefore, the size of the frame is unknown to the mobile station, it is infeasible for the mobile station to determine the location of the subsequently received frames of data, including any retransmission frames of data, in the block of data for reconstructing the block of data. Moreover, if the format of the discontinuous transmission time is unknown to the mobile stations, it is also not feasible or easily possible for the mobile stations to determine the location of any received frame of data within the block of data.
Therefore, there is a need, at least for IS-2000 system with supplemental channels variable data rate with non-continuous transmission and F-PDCH, to provide a system, method and apparatus for communication of a block of data and reconstructing the block of data at a receiving mobile station.